Signal suppresser for automotive radioreceivers



Oct. 24, 1933. H. SCHWARZE 1,931,525

SIGNAL SUPPRESSER FOR AUTOMOTIVE RADIORECEIVERS Filed March "I. 1932 HEHMHN EZ-HWHHZE dbkomq:

i l i l Patented Oct. 24, 1933 PATENT OFFICE SIGNAL SUPPRESSER FOR AUTOMOTIVE I RADIOREOEIVERS Herman Schwarze, Pontiac, Micln, assignor to General Motors Corporation, Detroit, Mich, a corporation of Delaware Application March 7,1932. Serial No. 597,360

10 Claims. ,(Cl. 123148) This invention relates to the art of radio re- -ception as applied to automotive vehicles.

One of the objects of this invention is to sup-.

press or substantially eliminate interference that isusually attendant upon the operation of the automotive power plant during radio reception. This is accomplished by providing a resistor or suppresser and incorporating the same in one of the essential elements of the ignition system, so as to be in circuit with the ignition circuit and to suppress the effect of the sparking impulses upon the radio equipment.

A further object of this invention is to provide an article of manufacture readily adaptable to existingautomotive equipment, whereby the desired results may be obtained. This has been accomplished by building into one of the essential elements of the ignition system a resistance element or suppresser unit that will normally be traversed by the sparking impulses of the automotive power plant. A further object of this invention is to properly locate a resistance unit in the-ignition system of an automotive vehicle so that it, will have maximum eflicicncy in reducing spark noises attendant upon radio reception. This has been accomplished in the instant invention by locating the resistance as closely as possible to a pair of sparking elements, for instance, the sparking terminal of the distributor cap and the segment of the rotor in which instance the resistor is connected directly to the segment and tothe wiping contact of the rotor. An alternative means in accomplishing a similar result is to connect the resistor directly between the wiping contact and the high tension terminal of the distributor cap.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing wherein'a preferred embodiment of one form of the present invention is clearly shown.

In the drawing: Fig. 1 is illustrative of one adaptation of the present invention, certain parts of the structure being broken away for the purpose of illustration.

Fig. 2 is a circuit diagram illustrative of the disclosed adaptation of the present invention.

Fig. 3 is a planview of one element of anignition unit depicting the preferred manner of incorporating the invention. v

Fig. i is a side elevation of the same.

Fig. 5 is a transverse sectional view substan-' tlally as indicated by the line and arrows 5-5 of Fig. 3.

Fig. 6 is a view showing a modification of the present adaptation. In the field of radio equipped vehicles one of the major problems that has to be contended with is that of suppressing or reducing interference upon the radio apparatus with which the vehicle is equipped. This source of trouble is particularly manifest in vehicles that are propelled by power plants that depend upon sparking impulses for ignition of their fuel charges. The problem is existant in practically all forms of that particular class of vehicles whether it be an aeroplane, airship, marine or a land vehicle, and hence applicant has selected the term automotive vehicle as descriptive of all vehicles of ,this general class whether it be the family automobile, the buss, motorcycle, flying machine, 1 airship or motor boat etc. In structures of this kind there is an ignition circuit corresponding more or less to that depicted in Fig. 2, and is in such close proximityto the radio apparatus with. which the automotive vehicle is equipped, that radio interference from that source cannot well be reduced or eliminated without, the incorporation in the said circuit of some physical means to accomplish that result. Applicant has found that the best and most efiicient solution of the problem is accomplished by building this physical means into one of the elements of the apparatus over which the spark impulses must traverse.

Referring particularly to Fig. 2 the ignition system usually incorporates a current source as the battery 10 grounded at 12 and thatvhas communicationby a conductor 14 with an ignition switch 16 after which the conductor joins a primary 18 at a point 20. A lead 22 joins the primary 18 with a circuit breaker mechanism 24 that provides a fixed contact 26 and a movable contact 28'periodically actuated by a cam 30. A secondary winding 32 has communication with the point 20 in the battery lead and has a conductor 34 usually known as the high tension con 'ductor and which customarily joins a high tension terminal 36 of a timer distributor 38 where electrical communication is made with a substantially stationarypoint 40 of, a rotor 42 carrying a revoluable contact or segment 44 that is periodically juxtaposedwith the sparking terminals 46 each of which has appropriate electrical communicationwith the spark gaps 48 assigned to. each of the engine cylinders'from which a common ground is provided as at 50. The system n usually provides a condenser 52 by-passed about the interrupter 24 and may or may notinclude a generator 54 in series with a cut-out relay 56 that is Joined to the battery lead 14 by conductor 58. The cam 30 and the rotor 42 are usually driven in timed relation or from the common shaft 60 as indicated in dot-and-dash lines in the diagrammatic illustration. In the prior art devices the elements 40 and 44 are connected by a conductor or bridging member of little or no resistance so that sparking impulses originating at the coil may be successfully transmitted to the spark gap 48 with which the rotor may be aligned.

In the preferred form of the invention and as here illustrated the rotor 42 embodies a resistance element 62 which has its terminals joined to the elements 40 and 44 so as to replace the usual bridging member, and so as to be in circuit with the secondary of the ignition coil and be traversed by the sparking impulses created thereby. In Figs. 1, 3, 4 and 5 the details 01 construction of the rotor have been illustrated, and comprise a channel or recess 64 along one side thereof and in substantial communication with the segment 44 and the contacting member 40. The resistance element 62 may have its ends joined directly to the elements 40 and 44, but it is preferred that the same be provided'with leads 66 and 68 by which the same may be joined to the elements 44 and 40 respectively. When the resistance element 62 is thus disposed within the recess 64 it may be secured therein by filling the recess with appropriate cement as indicated at 70. or the resistance element may be incorporated in the rotor blank as an insert at the time the element is molded into form.

As an alternative the resistance element may be similarly secured in the timer distributor cap 72 substantialhr as indicated in Fig. 6, in which instance the usual form of rotor 42 would be used in conjunction therewith. To accomplish this, the cap 72 is recessed at 74 to receive theresistor 62, and has its high tension terminal member 360 of a form that will permit the connection of the resistor 62 by its lead 66, while the lead 68 will join the wiping terminal 36?) contacted by the member 40. Here too. the resistor 62 may be secured in the cap 72 by cement as at '76 or the resistor may be incorporated in the body of the cap as an inset at the time of molding.

In either form of construction, whether in the rotor or the distributor cap, the suppresser element will be effectively connected into the circuit of the sparking impulses and will be operative to substantially eliminate interference with the radio receiver. That is to say, when an element of an ignition unit is equipped with a spark suppressing device as has been herein disclosed it is found that radio interference is efliciently suppressed so that operation of the radio receiver will not be disagreeable or impractical while the power plant of the vehicle is in operation.

While the form of embodiment oi! the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the .scope of the claims which follow.

What is claimed is as follows:

1. In an ignition unit for a radio equipped automotive vehicle, the combination comprising, an element for distributing sparking impulses created by the operation of said vehicle including a pair of contacting members, a resistance element directly connected with said contacting members,

said resistance element being housed by a recess provided in the distributing element.

2. In an ignition unit for a radio equipped automotive vehicle, the combination comprising, an element for distributing sparking impulses created by the operation of said vehicle including a pair of contacting members, a rotor having conductive parts one of which is engaged by one of said contacting members, and a resistor directly connected to both 01' said contacting members.

3. In an ignition unit for a radio equipped automotive vehicle, the combination comprising, an element, for distributing sparking impulses created by the operation of said vehicle including a pair of contacting members, said element providing a recess substantially communicating with said contacting members, a resistance element secured within said recess and directly with each of said contacting members.

4. In an ignition unit for a radio equipped automotive vehicle, the combination comprising, means for creating sparking impulses, means for transmitting said sparking impulses, an element for distributing the said spark ngimpulses, and means interposed in circuit between the creating means and the distributing means for suppressing the effect of said sparking impulses upon said radio equipment said interposed means comprising a resistor directly connected to the terminal parts of said distributing element.

5. In an ignition unit ior a radio equipped automotive vehicle, the combination comprising, means for creating sparking impulses, means for transmitting said sparking impulses, means for distributing the said sparking impulses, and means incorporated in the distributing means and traversed by said sparking impulses for sup pressing the efiect of the same upon the said radio equipment said incorporated means comprising a resistor directly connected to terminal members of the distributing means.

6. In an ignition system for an automotive vehicle and the like, a distributor comprising in 0mm bination, a cap member providing a plurality of terminals each having exposed parts on both sides of said cap, a rotor member having terminal parts cooperating with said cap terminals for distribution of sparking impulses, and a resistor carried by one of said members and directly connected to the respective terminal parts.

7. In an ignition system for an automotive vehicle and the like, a distributor comprising in combination, 9. ca; member providing a plurality of terminals each having exposed parts on both sides of said cap, a rotor member having terminal parts cooperating with said cap terminals for distribution oi sparking impulses, and a resistor carried by the cap directly connected to the respective parts of one of said terminals.

8. In an ignition system for an automotive-vehicle and the like, a distributor comprising in combination, a capmember providing a plurality of terminals each having exposed parts on both sides of said cap, a rotor member having terminal parts cooperating with said cap terminals for distribution of sparking impulses, and a resistor carried by the rotor directly connected to the said rotor terminal parts.

9. In an ignition unit for a radio equipped automotive vehicle, the combination comprising, an element for distributing sparking impulses created by the operation ofsaid vehicle including a pair of contacting members, a rotor having conductive parts, one of which is in electrical connection with one of said contacting members, and a resistor carried by the rotor-and directly electrically connected to both oi. vsaid conductive parts.

10. In an ignition unit for a radio equipped automotive vehicle, the combination comprising, an

element for distributing sparking impulses created by the operation of said vehicle includinz a pair 01' contacting members. a rotor having con- HERMAN BCHWARZI. 

